Integrated circuits are what power many of today's consumer electronics, for instance, cellphones, video cameras, portable music players, computers, etc. As customer demand improves integrated circuit performance, faster, more reliable, and higher-density circuits, need to be produced at a lower cost. Packaging goals of the future for these integrated circuits will be met by increasing the density of chips while reducing the number of internal electrical interconnections. Packaging with fewer interconnects can potentially shorten the circuit length, decreases potential failure points, reduces circuit resistance, and reduce inter-line capacitance or cross-talk. Various techniques, such as, flip chip, ball grid array (BGA), chip on board (COB), and multi-chip modules (MCM), have been developed to meet the continued demands for improving integrated circuit system performance.
MCM packaging is a design that enhances electrical performance by reducing circuit resistance and parasitic capacitance while reducing the size and weight of the total package. MCM package configurations mount several die onto a substrate, which permits a higher density per unit area than direct attachment of each individual die to a printed circuit board. Ultimately, as the demand for higher-density circuits continued, MCM package configurations needed to evolve to the next generational level.
For even higher density applications, MCM substrates have been stacked to provide a three-dimensional structure. Unfortunately, stacked MCM substrates are prone to expensive and complex layer formation, warpage and co-planarity issues, interconnection difficulties, heat dissipation problems and electromagnetic interference dilemmas. For example, impedance mismatches and capacitive interferences within interconnects between modules, may cause discontinuities in signal transmissions that can result in erroneous data transmissions. Additionally, heat dissipation problems are confounded by the use of heat sinks, which disrupt interconnect patterns between adjacent MCM substrates. Furthermore, high frequency applications on one MCM substrate can disrupt integrated circuit systems sensitive to such energy on adjacent MCM substrates.
Thus, a need still remains for an integrated circuit package system employing multiple substrates, each with one or more semiconductor chips, which reduces fabrication complexities and answers operational difficulties. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.